TRAJ50 and COVID-19: Comparison of TCR gene usage in the top 0.1% most abundant sequences showed that both TCRɑ gene segments (TRAV and TRAJ) and TRBJ now clustered by condition, with several gene segments overrepresented in healthy repertoires (TRAV25, TRAV30, TRAV8-1, TRAV36/DV7, TRAJ47, TRAJ50), COVID-19 repertoires (TRAV21, TRAV3), and PIMS-TS repertoires (TRAV10, TRAV1-1, TRAV26-2, TRAJ45 and TRAJ18; Fig. 3E, F and H).